Process for pasteurizing and deodorizing liquids



Nov. 26, 1935. 3 HQRNEMAN 2,022,419

PROCES FOR PASTEURIZING AND DEODORIZING LIQUIDS Filed Jan. 28, 1935 2 Sheets-Sheet 1 wwm Nov. 26,1935 .c. HC.)RNEMAN 2,022,419

PROCESSFOR PASTEU'R'IZING AND DEODORIZING LIQUIDS Filed Jan. 28, 1935 2 Sheets-Sheet 2 Patented Nov. 26, 1935 PROCESS FOR PASTEURIZING AND DEODORIZING LIQUIDS Herman C. Horneman, Danville, 11L, assignor to Research Laboratories of National Dairy Products Corporation, Inc., Baltimore, Md., a corporation of Maryland Application January 28, 1933, Serial No. 654,069

4 Claims. (01. 99-11) This invention relates to a method of pasteurizing, deodorizing and cooling liquids, especially to a method of pasteurizing, .eodorizing and cooling milk products such as milk or cream used directly or in the manufacture of butter,

cheese, ice cream and other dairy products.

The primary object of this invention is to provide a process whereby milk or cream with an imparted flavor or flavors, due to fermentation and/ or feeds can be restored to its natural flavor. While conventional methods of pasteurizing and cooling milk or cream do, to some extent, tend to improve the flavor of these products by par-,

tially volatilizing the off-flavor imparting substances from said products, the present invention augments and magnifies this volatilizing effect to such an extent as toreduce the offflavors to a negligible quantity in' the endproduct.

In carrying out the present invention, very complete subdivision of cream or other lactic fluid is obtained with consequent maximum deodorization. This result is secured by first compressing the lactic fluid with steam or other inert gas while pasteurizing and mixing the fluid with the gas, and producing initially, a division of the cream particles. The treatment of the cream is continued by introducing the compressed steam-water-cream mixture through a reduced outlet into a condition of reduced pressure, 1. e., a vacuum chamber, whence a second extremely I fine subdivision of the particles takes place. This is due to the release of the mixture from a state of compression to acondition of expansion.

This release results in instantaneous breaking up of the particles to a degree of subdivision heretofore unattained and takes place with violent and explosive force.

Briefly stated, subdivision of the particles is first carried out under a condition of compression immediately followed as a continuous step by greatly enhanced subdivision made possible by the instantaneous'release of the preliminary dividedparticles from a state of compression to a condition of violent and in fact explosive expansion. I l

The vacuum chamber is characterized .by being heated. water vapors and odoriferous volatiles and their attendant objectional return to the cream is prevented. Likewise, separation of liquid and vapor phase constituents is prolonged, and moreover,'

In this manner, condensation ofsteam-water mixture is concentrated by removal of moisture and odoriferous volatile substances, with the result that the end product has improved organolyptic qualities and a substantially slightly reduced moisture content from 5 that of the original cream. That is, although dilution will take place in the initial compression and shattering of the cream particles with steam, this water is removed in the subsequent expansion subdivision treatment and the final effect is one of concentration of the original cream.

A particular object of this invention is to provide a method whereby milk or cream or other milk products are improved by eliminating in large measure, volatile substances therefrom, thereby rendering them suitable for manufacture into cheese, butter and-ice cream products of excellent quality.

A further object is to combine the operation of pasteurizing, deodorizing and cooling milk or 20 cream in one compact unit, thereby reducing the amount of handling of these products and minimizing their exposure to metallic surface and other innocuous influences.

Other objects and novel features and. advantages of this invention will be apparent from the following specification and accompanying drawings hereinafter more fully described and claimed. The preferred form and arrangement of my improved method, as shown in the accompanying drawings, is as follows:

Referring to the drawings; Figure '1 is a side elevation, partly in section of one form of apparatus.

Figure 2 is a detail view of the distributor head. 5 Figure 3 is a side elevation, partly in section of another form of apparatus.

Figure 4 is a top view of the apparatus shown in Figure 3.

Figure 5 is a view of a further embodiment 40 of the invention.

um chamber, and has a removable cover for ready cleaning of the chamber. The liquidto be treated is introduced continuously into surge tank l0 through pipe 8 from a forewarmer, where it has been preliminarily heated to a suitable temperature. From a laterally extending outlet 5 pipe I l, as shown in Figures 4 and 6, of the surge tank In, the liquid is transferred through the pipe l2 and pipe I3 to the vacuum chamber 9, the reduced pressure in the latter and a greatly increased velocity imparted by a steam jet disposed in the pipe 12, obviating use of a pump. A steam line 14 has its jet or open or outlet end in the line i2 above the outlet II and steam is introduced in sufiicient quantity to heat the liquid in the line l2l3 to a pasteurizing temperature, which temperature is automatically maintained by a thermostatic control [5 activated from the bulb at Hi.

The cream-water-steam mixture from line |2- I3 is distributed in vacuum chamber 9 by a distributing head l1, shown in detail in Figures 2 and 8, through the narrow, preferably elongated or continuous, peripheral opening l8. Details of the construction of the distributor head I are shown in Figures 2 and 8 and will later herein additionally be referred to.

In this manner, the lactic fluid is subjected to a. compression treatment in line l2-I3 and then to an expansion treatment in the chamber 9, resulting in very complete subdivision of the cream particles.

At the opening l8 the pressure of the liquidsteam-water mixture in the line I 2-l3 is suddenly released, due to the reduced pressure in chamber 9 and is thrown with spontaneous and violent force downwards into the chamber. The vapors and gases released by the introduction of the liquid-steam-water mixture into the vacuum chamber 9 through head 11 are carried oil through theport l9 and pipe 29 to the condenser 2l and vacuum pump 22. The liquid portions of the cream or milk will coalesce and collect at the bottom of vacuum chamber 9 and will pass by outlet pipe 23 through the cooler system 24 and can be continuously removed and recovered by means of a suitable pump 25 through pipe 26.

Surrounding the chamber 9 is a spaced wall 21 constituting a jacket within which is circulated a heating medium such as gas or liquid, preferably hot water. The inlet and outlet for the circulating medium are indicated 9' and 9" respectively.

A preferred form of distributing head I! is iilustrated in detail in Figure 2 and supported on a sanitary T-coupling ll. This distributing head comprises two members 2829 adjustably connected by bolts 39 to vary the width of the spray outlet. The bolts are provided with wing nuts engaging springs disposed between the wing nut and the adjacent surface of the member 28. Interiorly of the member 28 are projections 30, through which the bolts extend and which projections are of equal length and of a size whereby suitable shims may be interposed between the bottom of the projections and the top surface of the member 29, to permit of an extremely fine and critical range of adjustment for the outlet opening l8. In this connection, the outlet opening i8 is substantially continuous or elongated and, as shown, is relatively narrow. The baflle 3| is connected to the head as shown and diverts the finely divided particles downwardly to reduce possibility of entrainment, as will later be described.

Referring to Figure 8, the head if comprises the two members 28, 29, are centrally connected by a single bolt 39 and ar ed about the bolt are a plurality of space members 28' having reduced ends 29' loosely disposed in the members 28 and 29 respectively. When it is desired to adjust the outlet opening between the members 29 and 29, suitable shims are fitted about the'reduced ends of the spacer members to assure a. very fine adjustment of the outlet opening l8. As will be understood, the provision of a distributor head I1 having a reduced, critically adjustable outlet l8 assists the injected steam in establishing a compression of the mixture in the line |2--.l3 and creating a pressure difierential between this line and chamber 9.

A suitable float-operated slide valve III, as shown in Figure 6, controls the outlet from the tank In, which will overcome any possibility of v releasing the vacuum in chamber 9 if the liquid reaches a predetermined depressed level, as when the cream supply temporarily stops.

The steam line I4 is projected into the line I 2 to have its outlet above the outlet from the tank I9. I find this is not only efficient in my process, but also overcomes any tendency for the steam to enter the surge tank I0 and produce interruption of continuous flow of cream or milk in the line I2l3. That is, the flow of the mixture in line l2-l3 is to the chamber 9. This direction of flow is induced by the influence of the vacuum in chamber 9 plus the velocity of the compressed mixture in line |2l3 resulting from the injection of steam through pipe l4 into the said line l2--l3.

The head I! is relatively small, as compared to the size of the chamber 9, as shown. It is preferably substantially centrally located, that is, sufliciently below the outlet port or ports l9 to prevent entrainment and far enough from the bottom of the chamber to give the falling particles projected from the head a sufiicient time for adequate separation out of the vapor and liquid phase constituents and coalescence and cooling of the latter. 40

The line l2l3 is of a length and diameter to enable the lactic fluid to be continuously supplied from tank H! to the head I! and during travel in said line the lactic fluid is simultaneously pasteurized and intimately mixed with the steam and broken up and sub-divided by the steam and by the effect of compression which it undergoes while in said line.

The heating jacket 21 assures that the inner wall surface of the chamber 9 will be at a constant temperature, and serves to reduce to a minimum the possibility of condensation of water vapors and condensable gases on the wall of the chamber, as well as produce a prolonged separation of vapor and odoriferous gases from the liquid phase particles. v

The heating jacket 21 serves to maintain the wall of the chamber 9 at all times heated to the temperature of the boiling point of the cream or slightly higher, corresponding to the conditions of 60 vacuum in chamber 9.

It will be observed that the cream is treated under controlled temperatures from the time it leaves the surge tank until withdrawn from the system.

Also, while the line |2l3 communicates with the zone of reduced-pressure, namely the vacuum chamber 9, and is therefore under the directional influence of. the reduced pressure in the vacuum 7 chamber, the mixture in the line l2|3 is actually under compression, e. g., the mixture in the line I 2l 3 is under a pressure of substantially one atmosphere. Hence there is created a pressure differential between the compressed mixture in the line |2- -|3 and the reduced pressure in the vacuum chamber 9..

This compression of the mixture traveling through the line l2--l3 is obtained by the cooperation of the restricted outlet l8 of the dis-,

tributor head 11 and the steam introduced through pipe l4. During passage through the line i 2-|3, and by reason of compression, the particles of. lactic fluid are shattered and subdivided, and concomitantly, pasteurization takes place.

In other words, as will be observed, the cream and steam are mixed under compression in the line I2-l3, whereby an initial and intimate subdivision of cream particles is obtained. This is followed by a further subdivision when the mixture expands violently upon being released in the chamber 9, due to the pressure of the fluid in line l2-l3 and the reduced pressure in vacuum chamber. Therefore, the cream is subjected to two conditions, namely an initial compression in the line- |2l3 and a subsequent violent expansion in chamber 9 upon release from this compressed condition. It will be seen then that intimate subdivision of the cream and the mixing thereof with the steam is obtained under a condition of pressure and in continuation of this step, the mixture is subjected to further subdivision under a condition where the pressure is substantially reduced. Hence, there takes place extremely fine subdivision of the cream due to thecombined factors of an initial positive pressure condition pumped continuously.

In Figure 5, I have illustrated an alternative arrangement in which one or more peripherally disposed spray nozzles I! are provided. These nozzles I! are preferably spaced apart and the jet openings -are constructed to project the mixture toward the center of the chamber and v slightly downwardly, to. facilitate the gravity,

fall of the liquid phase of the steam-cream-water mixture. These nozzles are of any suitable design, such as commonly used for production of powdered dairy products by a spray process.

The nozzles shown have a spirally grooved and loose member in advance of the outlet port and will produce the so'- called solid cone spray.

The disclosure in Figure 3 is substantially similar to Figure 1, except thereare a plurality of spaced suction outlets l9, as shown in Figure 4,

- and an ejector-condenser systems is utilized instead of a wet pump and condenser-as in Figure 1.

The pressure. differential between the mixture in the line l2-|3 and the vacuum chamber 9, and the relatively narrow outlet opening l8 in the head, causes a spontaneous andviolent separa-' tion of the mixturein the vacuum chamber.

That is, the liquid and vapor phases are discharged through the narrow elongated outlet 18 and are broken up or particulated into substantially a fog from which the cream or milk on the one hand and the water vapor and gases on the other separate out in the chamber 9.

The diameter of the line I 2l3 and the periph eral dimension of the members defining the outlet in the head, and the diameter of the steam inlet and the pressure of the steam are selected or controlled, to produce the required result within (1) the rangeof adjustment permitted for the outlet opening in the head, and (2) the range of the reduced pressure maintained in the vacuum 6 chamber and the size thereof. In other words, it is essential that these parts be so related that the proper pressure differential will be established and that suflicient time will be permitted before the mixture enters the chamber, (1) for intimate mixing of the steam and lactic fluid, (2) for reaching a temperature suflicient for pasteurization, and (3) for compressing the mixture to preliminarily subdivide the same. In this manner, the mixture discharged from the head will be subjected to violent expansion and separation of the volatile and non-volatile constituents, and the liquid phase is finely sub-divided. Therefore, due

to the disposition of the head with respect to the chamber, as described above, and the heated 2o inner wall surface of the chamber, the volatile constituents will be separated and drawn' off without objectionable condensation on the wall or entrainment of the non-volatile constituents, which latter will gravitate and be collected in coalesced condition at the bottom of the chamber.

The invention is applicable to milk, cream, ice cream mix and milk products-in general, and for 1 convenience, I shall describe the treatment of sour cream (any cream in which the titratable acidity calculated as lactic acid exceeds 25%) to improve the same and render it satisfactory for the manufacture of butter.

Conventional practice comprises reduction of the acidity of the sour cream to a point at which satisfactory churning may be accomplished. Normally this point lies within a range from .18 to 25%, as expressed lactic acid. Upon completion of the acid reduction, the practice is to pasteurize in any suitable manner. The neutralizing and pasteurizing steps exert some fiavor improve ing effects, due to the volatization of certain flavors.

By the processes now to be described, I find that more effective improvement of the cream is attained. I shall assume, as in ordinary cases, that the sour cream is collected in a suitable'vat with means for mixing and sampling and possesses variedpercentages of acidity.

v Process A The cream as received, is'warmed to a point where it can be conveniently handled with the usual dairy equipment. Normally, this temperature will not exceed 110 F., preferably 90-100 F.

'Thereafter, the acidity is reduced, if necessary,

by a neutralizing treatment as understood in the art. I find it preferable to operate with the acidity of the sour cream at app oximately .3% calculated as lactic acid.

After a suitable time has'been allowed for the action of the neutralizing agents, the cream is then quickly heated to a temperature of 150-165 F., and preferably not to exceed 170 F. in a conventional heater, such as one of the continuous type generally termed a flash pasteurizer.

The cream at this temperature is transferred to the tank If] through pipe 8. When proper level in tank I!) is attained, the float will open the valve and by virtue of the difference in pressure between the outside atmosphere and the chamber 9, in which a reduced pressure is being mainta'ined, the liquid willbe forced into the line l2-l3 and through the distributor head I! into the vacuum chamber.

As soon as flow is established, steam under a pressure of substantially 50 to 100 lbs. is introduced into the cream in the line l2 through the steam line l4, as shown in Figures 1 and. 3. The outlet of the steam pipe extends above the lateral outlet ll of the tank It]. This assures that the steam will travel in a direction toward the vacuum tank whereby (1) the pressure of the mixture in the line l2-l3 is increased, i. e., the mixture is compressed, (2) intimate mixing of the steam and cream is accomplished with subdivision of the cream, since no opportunity is presented for building a back pressure or forcing steam into the tank l0, and (3) the steam is introduced at a safe point and relatively close to the outlet of the tank, so that a maximum contact of liquid and steam is maintained from the tank to the vacuum chamber and distributor head.

In this steam treatment the latent heat of the steam is very largely transferred to thecream and 1) part of the cooled steam condenses and (a) the heat of condensation also is transferred to the cream, resulting in a cream-steam-water mixture having a pasteurizing temperature of substantially 185. F., (b) the condensation of the steam with sudden collapse of the steam bubbles upon coming in contact with relatively cooler cream will cause a breaking up of the fat globules with consequent release of volatile odoriferous substances occluded within the fat clumps, and (c) the heating effect, the release of volatiles and the uncondensed portion of the steam produces in cooperation with the restricted outlet of the distributor head a compression, i. e., a building up of pressure in the line |2-I3, and (2) the uncondensed steam exerts a sweeping action in that it serves as a carrier forthe volatile or vapor phase constituents of the cream released by the shattering actions and heating effect of the steam.

This heating or pasteurization of the cream and its intermixing with the steam, as well as the breaking up of the fat clumps with release of volatiles, takes place during the continuous passage of the compressed mixture from the tank and steam outlet to the distributor head I! and under the directional influence of the vacuum cooperating with the steam to direct'the flow to chamber 9.

In connection with the use of steam, it will be understood that other inert gases may be employed. Steam is most convenient and economical and it will be used in such quantities and pres sures as to raise the temperature of the mixture .to the pasteurizing temperature of substantially 185 F. The temperature of the cream in the line can be controlled (1) by regulating the amount of the steam or cream or both supplied to the line and (2) by regulating, initially the temperature of the cream.

Referring to Figure 2, the outlet l8 of the distributor head I! is adjusted, so that the total area of the peripheral opening is a small fraction, for example one-tenth (1 6) of the crosssectional area of the line l2--l3.

This fraction will be determined by the condition of the dream, i. e., the amount of deodorization required. In the case of feed flavors such as onion and garlic, which are relatively easily volatilized, the opening of the distributorhead.

can be set at a maximum. Again where the oilfiavors are of a more tenacious character and of fermentation or bacteriological origin, the opening is reduced to a minimum.

It will be observed that the line l2-l3 extends into the vacuum chamber and communicates therewith through the head I1 which is substantially centrally disposed in the chamber.

. On the outside of the head, there is maintained a condition of reduced pressure preferably 26" or more of vacuum. On the inside of the head is present a cream-water-steam mixture under suf- 10 ficient pressure as above described to produce a pressure differential of substantially one atmosphere. This will vary with the conditions of operation as outlined above, and the differential may be in some instances greater or less than one atmosphere.

By reason of the small area of the outlet opening l8 in the head and the pressure differential maintained as just described, the cream-watersteam mixture is ejected into the chamber with violent and spontaneous expansion. A fog of finely divided cream and water vapors and gases is produced. The finely divided cream particles of the fog gradually coalesce and drop to the bottom of the chamber where they are collected and continuously removed while the vapors and gases are withdrawn through the outlet l9 by the vacuum pump to the condenser system.

The relative fineness or division of the cream particles and consequent effective deodorization and rapidity of cooling, is greatly enhanced by the use of a distributing head having a substantially continuous elongated or peripheral and narrow opening. The sudden release of the cream at a pasteurizing temperature into the vacuum chamber with instantaneous cooling to the boiling point of the liquid is instrumental in preventing at the prevailing vacuum at which point the temperature of the cream normally approximates l30-l45 F., formation of grainy texture or a weak body in any resulting butter or manufactured milk product. For example, thelength of the peripheral opening in Figure 2 will be substantially nineteen (19) inches and the width of the opening will be substantially 0.025 inches and 5 the diameter of the line l2-l3 substantially two and one-half (2 /2) inches or in equivalent ratios.

By reason of the use of a distributor head and the spontaneous and violent ejection of the water-cream-steam mixture due to the pressure differential, I greatly reduce foaming and consequent cream losses through entrainment.

The inclined walls of the opening [8 and baflie 3| act to deflect the fog downward, so as to diminish the possibility of entrainment of the cream particles with the vapors and gases which are withdrawn'through the outlet I9. The area of the baflle is such that it will effectively deflect the major portion of the fog without, however, restricting the net free area between the outside periphery of the baffle and the internal wall surface of the chamber to such a point that the average velocity of the vapors does not attain a critical velocity of entrainment, e. g., twenty (20) feet per second for water vapor.

The chamber 9 is heated by means of the heating jacket 21 and the temperature of the heating jacket and of the inner exposed wall of the chamber is maintained'substantially constant and at the temperature corresponding to the boiling point of the cream under the conditions of vacuum being maintained and preferably slightly higher to prolong separation of liquid and vapor phase constituents and prevent condensation on the wall 01' the chamber, e. g., with av vacuum of substantially 26", the water circulating in the jacket is maintained at substantially 130-145 F. I find that by using a heated chamber under the conditions of temperature and vacuum set forth above, that the deodorizing eflect is increased, because of the fact that I can completely prevent any condensation of vapors or gases on the wall of the chamber and consequent return of separated odoriferous substances to the collected cream in the bottom of the chamber. By maintaining this increased temperature on the wall, I also prolong the evolution of steam or evaporation from, as well as consequent deodorization of, the creamparticles as they coalesce and drop.

It will, therefore, be seen that the initially warmed cream is intimately mixed with steam and subjected in the line l2-l3 in its passage to the evacuated chamber, to a pasteurizing treatment and concomitantly there takes place a breaking up of the fat clumps with resultant release of odoriferous volatile matter. The steam and vapors actas a carrier for such evolved gases. The resultant mixture is compressed and a pressure differential is set up between the reduced pressure maintained in the evacuated chamber and the compressed cream-steam-water mixture in the line. i

By reason of the narrow and elongated opening in the head and the pressure differential, the mixture is discharged with spontaneous and violent expansion into the heated vacuum chamber in 'a very finely divided condition. The head is positioned centrally with respect to the chamber,

whereby there is sufficient time for the separation of the liquid and vapor phases, so that (l) the cream will coalesce and drop without entraining vapors or odoriferous gases, and (2) the vapors and gases do not entrain the cream and also they are prevented from condensing by the heated chamber.

The substantially spontaneous and violent release of the mixture with creation of a fog produces (1) cooling of the liquid phase as well unpreviously released in the line I2--l3 continue to have this function in the chamber and are the vehicle by which the odoriferous substances are carried from the chamber to the condenser system. In this manner, deodorization is accomplished effectively and an improved cream is collected at the bottom of the chamber. Re-contamination is prevented since the chamber is heated, and thus condensation on the wall is prevented, as well as prolonged evaporation of water and evolution of gases from the cream particles assured.

The cream at substantially 130-145 F. is

withdrawn from the bottom outlet 23 of the chamber 9 and passed through the system of coolers 24 by means of a pump 25 and discharged through pipe 26. The speed or capacity of the pump 25 will be adjusted automatically or manually to remove the cooled cream at substantially the same rate as the liquid collects at the bottom of the chamber. No appreciable dilution of the treated cream will ensue inasmuch as the amount of dilution introduced by the condensation of the injected steam in line I2-I3 is evaporated and withdrawn in the vacuum chamber as described. That is, the cream-steam-water mixture is concentrated in the chamber 9 to remove both the stricted outlet at one end thereof, so as to pasvolatile odoriferous vapors and any has condensed in line l2-I3.

The cream collected'from pipe 26 is recovered in pasteurized condition, greatly improved as resteam which gards flavor and odor, and is of excellent quality 5 Process B This process is distinguished from process A 1 in that there is no initial reduction of acidity in the case of sour cream. That is, in this process the pasteurized deodorized cream is neutralized, if necessary, after discharge from the outlet 23 or the discharge pipe 26. In the event that the 20 cream under treatment has an initial and appreciable acidity, its pasteurization and deodorization is accomplished without recourse to an initial neutralization or acid reduction and without detrimental curd formations, due to the 25 breaking up of the cream in the line I2-I3 and the chamber 9 as described.

I have found that it is possible to pasteurize the sour cream, and by this process, in some cases, a better pasteurization is obtained. 7 30 It will be observed that with the present in vention, the cream is ejected into the vacuum chamber with violent and spontaneous expansion whereby the liquid and vapor phases are effectively separated. The vacuum chamber therefore constitutes a separating chamber in which the optimum amount of deodorized cream is recovered.

Further, it will be observed that with the present invention the cream is continuously pasteurized and partially deodorized in advance of the distributor head, and in this condition is ejected as described to assure a very thorough separation in the vacuum chamber. In other words, there takes place in the line l2-i3 not 4 only a pasteurization and a building up of pressure, but as well, an initial or partial separation of the liquid and vapor phases of the cream.

As heretofore described the cream is heated (1) in the line l2--l3 and (2) in the vacuum chamber, and in each case, while under the influence of the vacuum. In line l2-I3 there, of course, is no condition of vacuum while the mixture is traveling through the line under the conditions recited but the mixture is under the directional influence of the vacuum. This is accomplished continuously without hardening of the curd or curd constituents and the heating of steam. v

The term deodorizing as used in the claims,

' is meant to have its generally accepted definition of including the removal of both odors and flavors.

I claim:-

1. The process of pasteurizing and deodorizing lactic fluids comprising mixing steam at sufficient temperature and pressure with a fluid mass continuously traveling in a conduit,' having a reteurize and subdivide the fluid and compress the mixture in cooperation with said outlet sufliciently that when the mixture is immediately introduced in finely divided state in a. vacuum the mixture will instantaneously expand to a from said restricted outlet to a vacuum having a sufiiciently reduced pressure that the mixture upon release of compression will violently and spontaneously expand in all directions to substantially a fog-like state, and separating the liquid and vapor phase constituents of the fog.

2. The process of pasteurizing and deodorizing cream comprising mixing steam at sufilcient temperature and pressure with cream continuously traveling in a conduit, having a restricted outlet at one end thereof, so as to pasteurize and subdivide the cream and compress the mixture in cooperation with said outlet sufliciently that when the mixture is immediately introduced in finely divided state in a vacuum the mixture will instantaneously expand to a substantially foglike state, introducing the compressed mixture in such a finely divided state from said restricted outlet to a vacuum having a sufliciently reduced pressure that the mixture upon release of compression will violently and spontaneously expand in all directions to substantially a fog-like state, and separating the liquid and vapor phase constituents of the fog.

3. The process of pasteurizing and deodorizing lactic fluids comprising mixing steam at sufiicient temperature and pressure with a fluid mass continuously traveling in a conduit, having a restricted outlet at one end thereof, so as to pasteurize and subdivide the fluid and compress the mixture in cooperation with said outlet sufliciently that when the mixture is immediately introduced 5 in finely divided state in a vacuum the mixture will instantaneously expand to a substantially fog-like state, introducing the compressed mixture in such a finely divided state from said restricted outlet to a vacuum having a sufiiciently l0 reduced pressure that the mixture upon release of compression will violently and spontaneously expand in all directionsto substantially a foglike state, prolonging separation of liquid and vapor phase constituents of the fog and preventl5 ing any substantial condensation of vapor phase constituents of the fog, and separating the liquid and vapor phase constituents of the fog.

4. The process of pasteurizing and deodorizing lactic fluids comprising mixing steam at suificient 20 temperature and pressure with a confined traveling fluid mass so as topasteurize the same, and compress the mixture and sub-divide the fluid, immediately subjecting the mixture to a condition of reduced pressure such as to produce violent 25 and spontaneous expansion of the mixture to substantially a fog-like state, and separating the liquid and vapor phase constituents of the fog.

, HERMAN C. HORNEMAN. 

